In an image forming apparatus, an image formation result is conventionally adjusted for avoiding deviation in a position and a density of an image. A procedure for adjusting an image formation result includes, for example, forming a resist pattern corresponding to a mark to be used for adjusting the image formation result on a belt member for conveying paper for each color, and obtaining deviation (i.e., a correction value) between a resist pattern of a reference color and a resist pattern of a subject color, so as to correct positional deviation of an image of the subject color based on the correction value.
Furthermore, a technique to form a mark to be used for adjusting an image formation result at timing in connection with a process of a printing job is known. For example, Japanese Patent Application Laid-open No. 2008-003496 discloses a technique to form a mark to be used for adjusting an image formation result before processing a printing job when vibration of an image forming apparatus is detected during standby.